User interface on a display device



FIG. 1 is a front view of the user interface on a display device; and,

FIG. 2 is another front view thereof but with elements previously shown in broken lines removed, with the exception of the display device.

The broken line showing of the text, broken line regions and screen is included for the purpose of illustrating an active menu on a display device and forms no part of the claimed design. 

The ornamental design for a user interface on a display device, as shown and described. 